Heat exchanger tube support structure

Abstract

A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving apertures formed therein. Each aperture has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is divisional application of application U.S. Ser. No. 10 / 285,178 filed Oct. 31, 2002 now U.S. Pat. No. 6,810,101 which is hereby incorporated herein by reference. U.S. Ser. No. 10 / 285,178 is a continuation of U.S. Pat. No. 6,498,827 filed on Nov. 1, 1999 and issued on Dec. 24, 2002 which is hereby incorporated by reference.FIELD AND BACKGROUND OF THE INVENTION[0002]The invention relates generally to heat exchanger construction and more particularly to support plates for retaining tube array spacing within the heat exchanger.DESCRIPTION OF THE PRIOR ART[0003]The pressurized water vapor generators or heat exchangers, associated with nuclear power stations and which transfer the reactor-produced heat from the primary coolant to the secondary coolant that drives the plant turbines may be as long as 75 feet and have an outside diameter of about 12 feet. Within one of these heat exchangers, straight tubes through which the pri...

AI Technical Summary

Benefits of technology

[0008]The problems associated with the prior art tube support plates are largely overcome by the present invention which resorts to a stronger more corrosive resistant plate material such as stainless steel and by forming hourglass shaped tube holes in the support plates which minimize pressure drop by reducing local turbulence and are less likely to cause the deposition of magnetite and other particles on the surface of the support plates.

Problems solved by technology

These deposits block the bights formed between protruding members and thus cause undesirable increases in pressure drop which will in turn result in an increase in the secondary water level in the downcomer.

If corrective actions are not taken, the rising water level could potentially flood the steam bleed ports and the main feed water nozzles and result in a malfunction of the steam bleeding and the main feed water systems.

Corrective actions such as power derating, chemical cleaning or water slap are costly.

Moreover, the removal of deposits by chemical cleaning or water slap could damage the support plates.

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